// 简化的文件系统服务实现

use std::collections::HashMap;
use std::path::{Path, PathBuf};
use log::info;
use super::{BaseService, ServiceError, ServiceStatus};

// 文件类型
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum FileType {
    RegularFile,
    Directory,
    SymbolicLink,
    Device,
}

// 文件权限
#[derive(Debug, Clone, Copy)]
pub struct FilePermissions {
    pub owner_read: bool,
    pub owner_write: bool,
    pub owner_execute: bool,
    pub group_read: bool,
    pub group_write: bool,
    pub group_execute: bool,
    pub other_read: bool,
    pub other_write: bool,
    pub other_execute: bool,
}

impl Default for FilePermissions {
    fn default() -> Self {
        Self {
            owner_read: true,
            owner_write: true,
            owner_execute: false,
            group_read: true,
            group_write: false,
            group_execute: false,
            other_read: true,
            other_write: false,
            other_execute: false,
        }
    }
}

// 文件信息
#[derive(Debug, Clone)]
pub struct FileInfo {
    pub path: PathBuf,
    pub file_type: FileType,
    pub size: u64,
    pub permissions: FilePermissions,
    pub created: u64,
    pub modified: u64,
    pub accessed: u64,
}

// 简化的文件系统服务
pub struct FileSystemService {
    files: HashMap<PathBuf, FileInfo>,
    status: ServiceStatus,
}

impl FileSystemService {
    pub fn new() -> Result<Self, ServiceError> {
        info!("Creating new File System Service");
        
        Ok(FileSystemService {
            files: HashMap::new(),
            status: ServiceStatus::Stopped,
        })
    }
    
    // 创建文件
    pub fn create_file(&mut self, path: &Path, file_type: FileType) -> Result<(), ServiceError> {
        if self.status != ServiceStatus::Running {
            return Err(ServiceError::FileSystemError("Service not running".to_string()));
        }
        
        if self.files.contains_key(path) {
            return Err(ServiceError::FileSystemError(format!("File already exists: {}", path.display())));
        }
        
        let now = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .unwrap()
            .as_secs();
            
        let file_info = FileInfo {
            path: path.to_path_buf(),
            file_type,
            size: 0,
            permissions: FilePermissions::default(),
            created: now,
            modified: now,
            accessed: now,
        };
        
        self.files.insert(path.to_path_buf(), file_info);
        info!("Created file: {}", path.display());
        Ok(())
    }
    
    // 删除文件
    pub fn delete_file(&mut self, path: &Path) -> Result<(), ServiceError> {
        if self.status != ServiceStatus::Running {
            return Err(ServiceError::FileSystemError("Service not running".to_string()));
        }
        
        if self.files.remove(path).is_some() {
            info!("Deleted file: {}", path.display());
            Ok(())
        } else {
            Err(ServiceError::FileSystemError(format!("File not found: {}", path.display())))
        }
    }
    
    // 获取文件信息
    pub fn get_file_info(&self, path: &Path) -> Option<&FileInfo> {
        self.files.get(path)
    }
    
    // 列出目录内容
    pub fn list_directory(&self, path: &Path) -> Vec<&FileInfo> {
        self.files.values()
            .filter(|file| {
                if let Some(parent) = file.path.parent() {
                    parent == path
                } else {
                    false
                }
            })
            .collect()
    }
    
    // 更新文件大小
    pub fn update_file_size(&mut self, path: &Path, new_size: u64) -> Result<(), ServiceError> {
        if let Some(file) = self.files.get_mut(path) {
            file.size = new_size;
            file.modified = std::time::SystemTime::now()
                .duration_since(std::time::UNIX_EPOCH)
                .unwrap()
                .as_secs();
            Ok(())
        } else {
            Err(ServiceError::FileSystemError(format!("File not found: {}", path.display())))
        }
    }
    
    // 更新文件权限
    pub fn update_permissions(&mut self, path: &Path, permissions: FilePermissions) -> Result<(), ServiceError> {
        if let Some(file) = self.files.get_mut(path) {
            file.permissions = permissions;
            file.modified = std::time::SystemTime::now()
                .duration_since(std::time::UNIX_EPOCH)
                .unwrap()
                .as_secs();
            Ok(())
        } else {
            Err(ServiceError::FileSystemError(format!("File not found: {}", path.display())))
        }
    }
    
    // 检查文件访问权限
    pub fn check_access(&self, path: &Path, require_write: bool) -> Result<(), ServiceError> {
        if let Some(file) = self.files.get(path) {
            if require_write && !file.permissions.owner_write {
                return Err(ServiceError::FileSystemError("Write permission denied".to_string()));
            }
            
            if !file.permissions.owner_read {
                return Err(ServiceError::FileSystemError("Read permission denied".to_string()));
            }
            
            Ok(())
        } else {
            Err(ServiceError::FileSystemError(format!("File not found: {}", path.display())))
        }
    }
    
    // 获取文件系统统计信息
    pub fn get_stats(&self) -> FileSystemStats {
        let total_files = self.files.len();
        let total_size: u64 = self.files.values().map(|f| f.size).sum();
        let directories = self.files.values()
            .filter(|f| f.file_type == FileType::Directory)
            .count();
        let regular_files = self.files.values()
            .filter(|f| f.file_type == FileType::RegularFile)
            .count();
            
        FileSystemStats {
            total_files,
            total_size,
            directories,
            regular_files,
        }
    }
    
    // 创建目录结构
    pub fn create_directory_structure(&mut self) -> Result<(), ServiceError> {
        info!("Creating basic directory structure");
        
        // 创建根目录
        self.create_file(Path::new("/"), FileType::Directory)?;
        
        // 创建标准目录
        let standard_dirs = vec![
            "/bin", "/etc", "/home", "/tmp", "/var", "/usr", "/proc", "/dev"
        ];
        
        for dir in standard_dirs {
            self.create_file(Path::new(dir), FileType::Directory)?;
        }
        
        info!("Directory structure created successfully");
        Ok(())
    }
}

impl BaseService for FileSystemService {
    fn start(&mut self) -> Result<(), ServiceError> {
        if self.status == ServiceStatus::Running {
            return Ok(());
        }
        
        info!("Starting File System Service");
        
        // 创建基本目录结构
        self.create_directory_structure()?;
        
        self.status = ServiceStatus::Running;
        info!("File System Service started successfully");
        Ok(())
    }
    
    fn stop(&mut self) -> Result<(), ServiceError> {
        if self.status == ServiceStatus::Stopped {
            return Ok(());
        }
        
        info!("Stopping File System Service");
        
        // 清理文件系统（在实际系统中应该更谨慎）
        self.files.clear();
        
        self.status = ServiceStatus::Stopped;
        info!("File System Service stopped");
        Ok(())
    }
    
    fn status(&self) -> ServiceStatus {
        self.status
    }
}

// 文件系统统计信息
#[derive(Debug, Clone)]
pub struct FileSystemStats {
    pub total_files: usize,
    pub total_size: u64,
    pub directories: usize,
    pub regular_files: usize,
}

impl FileSystemStats {
    pub fn average_file_size(&self) -> f64 {
        if self.regular_files == 0 {
            return 0.0;
        }
        self.total_size as f64 / self.regular_files as f64
    }
    
    pub fn directory_ratio(&self) -> f64 {
        if self.total_files == 0 {
            return 0.0;
        }
        (self.directories as f64 / self.total_files as f64) * 100.0
    }
}